Wireless products and services have continued to expand to the point that finite resources of available communication spectrum are being overwhelmed. Industry has been forced to make dramatic changes, as it must adapt to accommodate the exponential demand on spectrum access, efficiency and reliability.
The Federal Communications Commission (FCC) in the United States, and its counterparts around the world, allocate radio spectrum across frequency channels of varying bandwidth. Various frequency bands may cover, for example, broadcast radio, television, cellular phones, citizen's-band radio, pagers and so on. As more devices go wireless, an increasingly crowded radio spectrum needs to be shared.
Further, the FCC and its counterparts allocate the frequency channels only to the incumbent devices that have license to the radio spectrum. However, there is a small portion of the radio spectrum left for allocation to an increasing number of emerging wireless devices. Although the radio spectrum is almost entirely allocated to the licensed/incumbent devices, not all the licensed devices use the allocated frequency channels. At least at some geographical locations or at some time period, a large portion of allocated spectrum may be sitting idle, even though it is officially accounted for.
Cognitive radio is a paradigm for wireless communication in which either a network or a wireless device uses spectrum that are licensed to other users or systems on a temporary secondary basis. This type of secondary access of unlicensed spectrum by a secondary system or cognitive device has to ensure minimum interference to the licensed users.
Accordingly, there exists a need for method and apparatus for dynamic spectrum allocation in a wireless communication system.
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